Vitamin K antagonist therapy is effective against stroke, but it is considered unsuitable for up to 50% of patients as it is difficult to control international normalised ratio and bleeding on vitamin K antagonist. There is a need for an effective, safe and easy-to-use antithrombotic therapy for AF patients, unsuitable for vitamin K antagonist.

The Data Monitoring Committee recommended early study termination at first analysis of efficacy on 28 May 2010. Ninety four per cent of patients received apixaban 5mg bid and 91% patients received acetylsalicylic acid ≤162mg daily with median follow-up to one year. Total serious adverse events for apixaban were 1,040 and 1,230 for acetylsalicylic acid.

One thousand patients were treated with apixaban for one year, instead of acetylsalicylic acid. The study expects to prevent 18 strokes, mostly larger, 10 deaths and 31 cardiovascular hospitalisations at a cost of two major bleeds.